Effect of Nd on microstructure and mechanical properties of Mg-7Gd-0.5Zr alloy

Alloying studies of Mg-Gd system alloys are an important way to improve alloy properties, reduce Gd content, and thus cost and density. Nd is excellent in promoting aging precipitation and enhancing heat resistance properties. In this work, low Gd content Mg-7Gd-xNd-0.5Zr (x = 0, 0.5, 2, 3.5 wt%) alloys were prepared by melting casting and processed by solution aging. The effects of Nd on the microstructure and mechanical properties of the aged alloys were investigated by SEM, XRD, EDS, TEM, and electron tensile testing machine. The findings show that the Nd-free alloy consists mainly of <<-Mg and Mg5Gd, and after Nd addition, a new phase Mg41Nd5 is generated and the precipitation of the Mg5Gd phase is promoted, and due to the heterogeneous nucleation ability of Mg41Nd5 particles leads to grain refinement. The principal pre-cipitate phases in the matrix and grain boundaries of Nd-containing alloys are the beta ' phase, which is the alloy's primary strengthening phase. Due to the influence of fine grain strengthening and precipitation strengthening, the ultimate tensile strength of the Mg-7Gd-2Nd-0.5Zr alloy achieves a maximum of 328 MPa and 294 MPa at ambient temperature and 250 degrees C, respectively.(c) 2022 Elsevier B.V. All rights reserved.